This project will develop and test the protype of a new instrument for measuring hrizontal, vertical, and torsional eye positions eye positons noninvasively, unobtrusively, and simultaneously. Testing will be by measuring a simulated eye, and by comparing measurements on humans with those made by other instruments. The prototype will have a directional resuolution of better than 2 arc minutes over 45 degrees, an accuracy of better than 10 arc minutes over 20 degrees. Each measured variable will be sampled at least 500 times per second, and the measurements will not be sensitive to ambient illumination, accommodation, pupil size, or head movements of up to 1 cm (0.5 cm in depth). The instrument will have advantages over instruments costing about ten times as much. Applications appear in diverse areas such as assessment of visual functioning, particularly in non-verbal or non-cooperative individuals; driving displays for pilots in aerospace environments; pharmacological testing; enabling totally handicapped persons to communicate; reading analysis; and evaluation of advertising material. Analysis of measured eye-movements is a principal tool for evaluating the sensory, perceptual, and cognitive characteristics of human infants.